10.1. METHODS OF IMAGING STUDY
The imaging study holds a high position in the diagnostic of diseases and injuries of the digestive organs. The emergence of the new highly informative techniques of imaging, such as CT, MRI, PET, significantly increased the accuracy of diagnostic radiology of diseases and injuries of the gastrointestinal tract but did not reduce the value of the X-ray method of investigation.
10.1.1. Radiological method
X-ray examination of the digestive system always includes transillumination and X-ray (survey and spot), as due to the anatomical and physiological peculiarities of the digestive system, it is impossible to obtain the detection of the diseases only by means of images in standard view.
The gastrointestinal tract is a hollow indiscrete pipe, the structure and functions of which depend on its region. Thus, different techniques are used in order to examine the pharynx, esophagus, stomach and small and large intestines. However, there are general rules of X-ray examination of the gastrointestinal tract. It is known that the esophagus, stomach and intestines absorb X-ray radiation as well as neighbouring organs, so in most cases, the artificial contrast is used, that is the introduction of RCA or gas into the cavity of the digestive tract. Each study of the gastrointestinal tract must begin with a review of X-rays of the chest and the abdomen, because many diseases and lesions of the abdomen can trigger the lungs and pleura reaction, and esophageal diseases can displace the neighbouring organs and distort the mediastinum (Fig. 10.1).
The survey X-rays of the abdomen allow revealing the signs of hollow organ perforation in the form of appearance of free gas in the suprajacent regions (under the diaphragm in the upright position of the patient or under the abdominal wall in the horizontal position). (Fig. 10.2). Moreover, the radiopaque foreign bodies are clearly visible on transillumination with X-rays or on the survey X-ray (Fig. 10.3), as well as accumulation of fluid in the flank of the abdomen, gas and fluid in the intestines, areas of calcification. If the diagnosis is unclear, the artificial contrast of the gastrointestinal tract is applied. The most common is barium sulphate - high contrast harmless substance, and also the water-soluble contrast drugs - sodium amidotrizoate